Grease for slide bearing

Abstract

Grease for a slide bearing, which can suppress unusual noise attributable to a slip caused between a shaft and a bearing when a machine is stopped. In slide bearing grease 24 supplied to between a slide bearing 16 formed of a porous sintered alloy-made bushing having pores 30 impregnated with lubricating oil 31 and a shaft 22 inserted in the slide bearing 16 and supported to be slidingly rotatable in the circumferential direction, the slide bearing grease 24 employs base oil having dynamic viscosity of 10-70 mm 2 /s at 40° C. and exuding under a load of the shaft 22 to form an oil film 35 between the slide bearing 16 and the shaft 22.

1. A slide bearing assembly comprising:
 a slide bearing that is part of an excavator with front end attachments having joints, said slide bearing being formed of a porous sintered alloy-made bushing having pores; 
 a shaft inserted in said slide bearing and supported to be slidingly rotatable in a circumferential direction; 
 a lubricating oil impregnated in said pores of the bushing, 
 wherein the lubricating oil exudes from said pores while the slide bearing slides relative to the shaft and lubricates the interface between the slide bearing and the shaft; 
 a slide bearing grease supplied between the slide bearing and the shaft; 
 wherein the slide bearing grease contains a base oil having a dynamic viscosity lower than that of said lubricating oil, and 
 while the relative sliding between the slide bearing and the shaft is maintained in a stationary state, the base oil of the slide bearing grease exudes under a load of said shaft to form an oil film between said slide bearing and said shaft. 
 
     
     
       2. The slide bearing assembly according to  claim 1 , wherein the relative sliding between the slide bearing and the shaft occurs in a high load, low speed operation. 
     
     
       3. The slide bearing assembly according to  claim 1 , wherein the slide bearing is in one of a connection between a boom and an upper body, an arm to the boom and a work implement to the arm of an excavator. 
     
     
       4. The slide bearing assembly according to  claim 1 , wherein the slide bearing has a distributed load across the bearing surface and is under high contact pressure in the stationary state. 
     
     
       5. The slide bearing assembly according to  claim 1 , wherein the base oil has a dynamic viscosity of 10-70 mm 2 /s at 40° C. 
     
     
       6. The slide bearing assembly according to  claim 5 , wherein the lubricating oil has a dynamic viscosity of 220-1500 mm 2 /s at 25.5° C. 
     
     
       7. A slide bearing assembly comprising:
 a slide bearing installed in joints of a front end attachment of an excavator and formed of a porous sintered alloy-made bushing having pores; 
 a shaft inserted in said slide bearing and supported to be slidingly rotatable in a circumferential direction; 
 a lubricating oil impregnated in said pores of the bushing, 
 the lubricating oil exuding onto the sliding surface between the slide bearing and the shaft and lubricating between the slide bearing and the shaft, when the slide bearing and the shaft slide relative to each other; and 
 slide bearing grease supplied between the slide bearing and the shaft; 
 the slide bearing grease having at least a solid lubricant and containing a base oil having a dynamic viscosity lower than that of said lubricating oil, and 
 the base oil exuding under a load of said shaft and forming an oil film between said slide bearing and said shaft while the relative sliding between the slide bearing and the shaft is maintained in a stationary state. 
 
     
     
       8. The slide bearing assembly according to  claim 7 , wherein the relative sliding between the slide bearing and the shaft occurs in a high load, low speed operation. 
     
     
       9. The slide bearing assembly according to  claim 7 , wherein the slide bearing is in one of a connection between a boom and an upper body, an arm to the boom and a work implement to the arm of an excavator. 
     
     
       10. The slide bearing assembly according to  claim 7 , wherein the slide bearing has a distributed load across the bearing surface and is under high contact pressure in the stationary state.